Diehl

Diehl is a spoiled and pretentious rich kid from Torble University whose father is an "elite IMa official." They have a huge estate with tons of training gadgets and over 60 monsters. Diehl constantly brags about how they are the most efficient ranch in IMa, and even states that they turn monsters out into the street who can't hack it.

At one point, Rio actually punches him in the face, effectively ending any chance of partnership you had with him. From there on out he becomes an annoying rival, sponsoring Wit in his research to find a way to beat you. When Wit suggests using machines to enhance his monsters, though, Diehl realizes he's gone too far and closes down his ranch.

He comes to your ranch and warns you about what Wit said, and then vows to go back and reopen his ranch, this time with the right mindset.